How to estimate amount of required absorption in a small room

Hi Ethan, I'am very pleased to meet You.

How do You estimate amount of absorbtion in a small room. (especially in LF)
Do You use Sabine equation to estimate amount of absorption that will give You a certain RT ?
Is there another method - more accurate in small rooms?

Small room = under 60 cubical meters.

Thanks.

At low frequencies, it's not possible to have too much absorption. So my advice is to have as many bass traps as you can afford and fit in the room. A small room will never be perfectly flat at low frequencies, so the more traps you have the closer you'll get.

RT60 calculations are meant for large rooms that have true reverb. Like an auditorium or at least a classroom that can seat 30 or more people. A small room like you'll find in a home doesn't have real reverb unless the room is totally empty with only bare surfaces.

In a small room, how much absorption is best depends on whether the floor is carpet or reflective, how many curtains you have and how thick they are, and so forth. For mid and high frequencies my general advice is to treat the side-wall and ceiling reflection points, plus the wall behind you if that wall is not far away. That's often enough. If you find the room is still too live sounding to hear clearly, you can always add a few more panels.

--Ethan